Although international law and the Charter of the United Nations define a doctrine of just war, some critics have argued that the U.S. has become an empire that can no longer be bound by such doctrine. On the contrary, I maintain that we must retain just war doctrine as a normative base from which to critique the U.S. and its preemptive wars against terrorism. Neither the Afghanistan nor the Iraq war has been a just war. By its imperialist intentions and barbarous actions, the U.S. government has shown itself no longer to be a legitimate authority with the moral justification to begin or conduct a war. Such subversion of democratic deliberation requires a moral force to mobilize resistance from below. Since no war initiated by the undemocratic elite of the U.S. Empire could possibly be just, we have a conscientious obligation to become revolutionary pacifists against any wars called by such an illegitimate government. In contrast to universal pacifism, a context-justified revolutionary pacifism can be defended as a coherent moral and political position.